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NCT07598708PHASE2, PHASE3Recruiting

A Study to Investigate the Effects of Cleminorexton Compared With Placebo in the Treatment of Participants With Central Disorders of Hypersomnolence

Centessa Pharmaceuticals (UK) Limited

Start Date

5/29/2026

Completion Date

12/31/2027

Summary

Narcolepsy Type 1 (NT1) and Narcolepsy Type 2 (NT2) are rare conditions that make people feel very sleepy during the day (often referred to as excessive daytime sleepiness \[EDS\]). People living with these conditions might find it hard to stay alert and pay attention when they are at school, working, driving, or performing other daily activities. While all conditions result in feeling sleepy, there are some differences in other common symptoms: * NT1: People with NT1 often feel very tired during the day and experience cataplexy. Cataplexy is a sudden loss of muscle strength, which can cause someone to collapse or lose control of their muscles for a short time. This is often triggered by strong emotions, such as laughter or surprise. They may also have trouble sleeping well at night. * NT2: People with NT2 feel sleepy during the day, just like NT1, but they do not have cataplexy. Orexin is a protein in the brain that helps coordinate a system that plays an important role in helping people to stay awake during the daytime. Cleminorexton is designed to mimic the action of orexin. The purpose of this study is to see how safe and tolerable cleminorexton is in NT1 and NT2 and learn about what the drug does to the body. Another goal of the study is to see if cleminorexton can help people with NT1 and NT2 feel less sleepy and make other symptoms better.

Detailed Description

The SAPPHIRE Clinical Trial The Sponsor may in the future, through a protocol amendment, expand the protocol to include participants with idiopathic hypersomnia (IH) in Cohort C.

Eligibility Criteria

Age Range: 18 years to 70 years

Key Inclusion Criteria: * 18-70 years of age * Body Mass Index (BMI) within the range ≥ 17.0 and ≤ 45 kg/m\^2 (inclusive) * Meets the diagnostic criteria of Narcolepsy Type 1 (NT1) or Type 2 (NT2) according to International Classification of Sleep Disorders, 3rd edition, Text Revision edition (ICSD-3-TR) criteria * Is willing and able to discontinue all medications used for the treatment of narcolepsy * Is willing and able to adhere to additional protocol requirements Key Exclusion Criteria: * Medical disorder other than NT1 or NT2, that is associated with excessive daytime sleepiness (EDS) * Presence of significant cardiovascular, pulmonary, gastrointestinal, hepatic, renal, hematological, malignancy, endocrine, neurological or psychiatric disease

Interventions

DRUG

cleminorexton

DRUG

Placebo

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Conditions

Narcolepsy Type 1Narcolepsy Type 2

Locations

Colorado Springs, Colorado

Colorado Springs, Colorado 80918

United States

Miami, Florida

Miami, Florida 33176

United States

Miami Lakes, Florida

Miami Lakes, Florida 33014

United States

Flowood Mississippi

Flowood, Mississippi 39232

United States

Denver, North Carolina

Denver, North Carolina 28037

United States

Huntersville, North Carolina

Huntersville, North Carolina 28078

United States

Cincinnati, Ohio

Cincinnati, Ohio 45245

United States

Dublin, Ohio

Dublin, Ohio 43017

United States

Columbia, South Carolina

Columbia, South Carolina 29201

United States

Sugar Land, Texas

Sugar Land, Texas 77478

United States